Oblong Hinge Friction Mechanism for Thin Computing Devices
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Solution Overview
Problem
Existing hinged devices in thin form factors face challenges in providing durable, reliable, and space-efficient friction profiles that allow for orientation-specific resistance to rotation, especially as devices become thinner and bezels shrink.
Innovation Solution
The use of oblong friction shafts and bands with oblong apertures that provide orientation-specific friction levels, featuring multiple contact zones and a pop-up mechanism to ensure low resistance for easy opening and high resistance for stable orientation, while being wear-resistant and compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional hinge mechanisms are used in thin devices, then device thickness is reduced, but reliability and durability of the friction profile deteriorate
Solution Approach 1:
The friction shaft is designed with non-circular cross-section (oval, rectangular, or triangular) to create orientation-dependent friction characteristics. This local geometric modification enables different friction levels at different rotational positions without increasing overall component size, thereby maintaining thin device profile while improving friction profile reliability
Solution Approach 2:
The friction shaft employs asymmetric cross-sectional geometry where the moment of inertia varies with rotational orientation. This asymmetry creates high friction at desired orientations (e.g., laptop operating positions) and low friction during opening/closing transitions, providing reliable orientation-specific friction control in a compact form factor
2Stability of the object's composition
If friction resistance is increased for stable orientation, then orientation stability is improved, but ease of operation for opening/closing deteriorates
Solution Approach 1:
The friction characteristic is made dynamic and orientation-dependent through the non-circular friction shaft geometry. The system automatically provides high friction when the shaft aligns with principal axes (stable orientations) and low friction during transitional positions (opening/closing), enabling both stability and ease of operation without manual adjustment
Solution Approach 2:
The friction parameter changes with rotational orientation due to the varying moment of inertia of the non-circular shaft. As the shaft rotates, the effective friction coefficient transitions between high and low states based on orientation, automatically facilitating easy opening/closing while maintaining stable positioned states
3Length of moving object
If hinge assembly size is reduced for thin devices, then device thickness is reduced, but wear resistance and durability deteriorate
Solution Approach 1:
The friction shaft is designed as a thin-walled hollow structure with non-circular cross-section. This thin-film approach reduces material usage and assembly size while the optimized wall thickness and geometric shape maintain sufficient wear resistance for the required durability lifecycle
Solution Approach 2:
The hinge assembly utilizes material composition optimization where the friction shaft may employ surface treatments, coatings, or composite material structures that enhance wear resistance without increasing component size, allowing thin profile maintenance while achieving required durability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves durable, reliable, and space-efficient friction profiles that maintain desired orientations with reduced wear, allowing for easy one-handed opening and stable positioning, even in thin devices with minimal bezel space.
Implementation Method 1
an oblong friction shaft and a friction band secured to the first portion and defining an oblong aperture configured to receive the oblong friction shaft... provide a relatively low resistance to rotation and at the open orientation the major axis of the oblong shape of the friction shaft is rotated to a non-parallel alignment relative to the major axis of the oblong shape of the aperture to provide a relatively high resistance to rotation
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
The description relates to hinged devices, such as hinged computing devices. One example can include a first portion and a second portion that are rotatably secured relative to a hinge axis through a range of rotation from a closed orientation to an open orientation. The example can also include an oblong friction shaft and a friction band secured to the first portion and defining an oblong aperture configured to receive the oblong friction shaft. At the closed orientation a major axis of the oblong friction shaft is aligned with a major axis of the oblong aperture to provide a relatively low resistance to rotation and at the open orientation the major axis of the oblong friction shaft is rotated relative to the major axis of the oblong aperture to provide a relatively high resistance to rotation.